diff --git a/Fabric.Backend.Center/src/common/version.ts b/Fabric.Backend.Center/src/common/version.ts
new file mode 100644
index 0000000..c8fa5ee
--- /dev/null
+++ b/Fabric.Backend.Center/src/common/version.ts
@@ -0,0 +1,7 @@
+export const FABRIC_PROTOCOL_VERSION = '1';
+
+export function normalizeVersion(input?: string): string {
+  if (!input) return FABRIC_PROTOCOL_VERSION;
+  const v = input.trim();
+  return v;
+}
diff --git a/Fabric.Backend.Center/src/nodes/nodes.controller.ts b/Fabric.Backend.Center/src/nodes/nodes.controller.ts
index 867f8ed..b150778 100644
--- a/Fabric.Backend.Center/src/nodes/nodes.controller.ts
+++ b/Fabric.Backend.Center/src/nodes/nodes.controller.ts
@@ -6,6 +6,7 @@ import {
   ForbiddenException,
   Get,
   Headers,
+  HttpException,
   NotFoundException,
   Param,
   ParseIntPipe,
@@ -25,6 +26,7 @@ import {
   signCanonical,
   verifyRequestTime,
 } from '../common/hmac';
+import { FABRIC_PROTOCOL_VERSION, normalizeVersion } from '../common/version';
 
 @Controller('nodes')
 export class NodesController {
@@ -40,7 +42,23 @@ export class NodesController {
     @Headers('x-fabric-signature') signature?: string,
     @Headers('x-fabric-timestamp') timestamp?: string,
     @Headers('x-fabric-nonce') nonce?: string,
+    @Headers('x-fabric-version') fabricVersion?: string,
   ) {
+    const requestedVersion = normalizeVersion(fabricVersion);
+    if (requestedVersion !== FABRIC_PROTOCOL_VERSION) {
+      throw new HttpException(
+        {
+          error: {
+            code: 'FABRIC_VERSION_NOT_SUPPORTED',
+            message: `unsupported protocol version: ${requestedVersion}`,
+            retryable: false,
+          },
+          supportedVersion: FABRIC_PROTOCOL_VERSION,
+        },
+        400,
+      );
+    }
+
     const secret = process.env.CENTER_SHARED_SECRET as string;
     if (!signature || !timestamp || !nonce || !verifyRequestTime(timestamp)) {
       throw new ForbiddenException('invalid hmac headers');
@@ -88,6 +106,7 @@ export class NodesController {
 
     return {
       status: 'accepted',
+      negotiatedVersion: FABRIC_PROTOCOL_VERSION,
       node: {
         id: saved.id,
         nodeId: saved.nodeId,
diff --git a/docs/TODO-backend-center-guild.md b/docs/TODO-backend-center-guild.md
index b33d788..dda3af3 100644
--- a/docs/TODO-backend-center-guild.md
+++ b/docs/TODO-backend-center-guild.md
@@ -66,7 +66,7 @@
 - [x] 鉴权方案定稿（node token / HMAC）
 - [x] 注册握手协议文档化
 - [x] 错误码与重试策略统一
-- [ ] 版本协商（`X-Fabric-Version`）
+- [x] 版本协商（`X-Fabric-Version`）
 
 ---
 
diff --git a/docs/center-guild-handshake-v1.md b/docs/center-guild-handshake-v1.md
index 6427618..04bae41 100644
--- a/docs/center-guild-handshake-v1.md
+++ b/docs/center-guild-handshake-v1.md
@@ -21,6 +21,7 @@
 ```
 
 ### Required Headers
+- `X-Fabric-Version`: 协议版本，当前固定为 `1`
 - `X-Fabric-Timestamp`: ISO8601 UTC 时间（如 `2026-05-12T11:00:00.000Z`）
 - `X-Fabric-Nonce`: 随机字符串（建议 UUID）
 - `X-Fabric-Signature`: HMAC-SHA256 十六进制串
@@ -84,7 +85,10 @@ signature = HMAC_SHA256_HEX(CENTER_SHARED_SECRET, canonicalString)
 ## 7. 版本协商（预留）
 当前版本：`v1`
 
-后续建议在请求头增加：
+当前实现要求请求头：
 - `X-Fabric-Version: 1`
 
-以支持协议平滑升级。
+若版本不匹配，Center 返回：
+- `400`
+- `error.code = FABRIC_VERSION_NOT_SUPPORTED`
+- `supportedVersion = "1"`